Effect of silphenylenesiloxane units on the thermal stability of poly[methyl(trifluoropropyl)siloxane]

Abstract

AbstractA series of poly[methyl(trifluoropropyl)siloxane‐co‐silphenylenesiloxane] (PMTFPS‐co‐SPS) was synthesized by condensation polymerization of methyltrifluoro‐propylsiloxanediol and 1,4‐bis(dimethylsilyl)benzene. Their chemical structures were investigated using gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and dynamic thermomechanical analysis (DMA). The effect of silphenylenesiloxane (SPS) units on the thermal stability of poly[methyl(trifluoropropyl)siloxane] (PMTFPS) was studied by thermogravimetric analysis (TGA), isothermal degradation tests, quantum chemical calculation, and pyrolysis‐gas chromatography–mass spectrometry (Py‐GCMS). The results showed that the thermal stability of PMTFPS improved with the introduction of SPS units into the backbone. The temperature for 5% mass loss in PMTFPS increased by 63°C under a nitrogen atmosphere. Additionally, the mechanism by which the SPS units improve the thermal stability of PMTFPS was also investigated.